Hwy 1 north of the bay area vs. big sur?

Naio, with your little rig (a van conversion), you can go anywhere!! Both north and south are great. Depends a lot on the time of year. Oddly, the views are better in the winter -- not so much low cloud and fog. In either case, north to south is better than south to north, so that you are that much closer to the ocean (not to mention the cliffside). In December, you can often see whales spouting far out to sea, sometimes lots of them.

Take lots of time to do this trip. There is so much to do and see. Great hiking, great photography, great seafood (especially in Monterey). Redwoods right by the ocean (in Big Sur). Fun, fun, fun!